PHP form sending through email

Hi Guys/gals

Recently bought a template so i could start learning and create my first site, but i have come stuck on the Feeback form.

I know how to get introduce the mailto: code to send email, but what i really want is a php code to do it for me. here is what i have so far.

Form Code:

<form id="ContactForm" action="form.php" method="post">
            <div>
             <label><span class="input"><input type="text" value="Name:" onBlur="if(this.value=='') this.value='Name:'" onFocus="if(this.value =='Name:' ) this.value=''" /></span></label>
             <label><span class="input"><input type="text" value="E-mail:" onBlur="if(this.value=='') this.value='E-mail:'" onFocus="if(this.value =='E-mail:' ) this.value=''" /></span></label>
             <label><span class="input"><input type="text" value="Subject:" onBlur="if(this.value=='') this.value='Subject:'" onFocus="if(this.value =='Your Country:' ) this.value=''" /></span></label>
             <span class="textarea"><textarea onBlur="if(this.value=='') this.value='Your Message:'" onFocus="if(this.value =='Your Message:' ) this.value=''"  >Your Message:</textarea></span>
            </div>
            <div class="alignright">
             <a href="#" class="link" onClick="document.getElementById('ContactForm').reset()"><span><span>clear</span></span></a>
             <a href="#" class="link" onClick="document.getElementById('ContactForm').submit()"><span><span>send</span></span></a>
            </div>
           </form>

And here is the PHP:

<?php
function spamcheck($field)
  {
  //filter_var() sanitizes the e-mail
  //address using FILTER_SANITIZE_EMAIL
  $field=filter_var($field, FILTER_SANITIZE_EMAIL);

  //filter_var() validates the e-mail
  //address using FILTER_VALIDATE_EMAIL
  if(filter_var($field, FILTER_VALIDATE_EMAIL))
    {
    return TRUE;
    }
  else
    {
    return FALSE;
    }
  }

if (isset($_REQUEST['email']))
  {//if "email" is filled out, proceed

  //check if the email address is invalid
  $mailcheck = spamcheck($_REQUEST['email']);
  if ($mailcheck==FALSE)
    {
    echo "Invalid input";
    }
  else
    {//send email
$name = $_REQUEST['name'] ;
    $email = $_REQUEST['email'] ;
    $subject = $_REQUEST['subject'] ;
    $message = $_REQUEST['message'] ;
    mail("email@person.com", "Subject: $subject",
    $message, "From: $email" );
    echo "Thank you for using our mail form";
    }
  }
else
  {//if "email" is not filled out, display the form
  echo "<form method='post' action='mailform.php'>
  Email: <input name='email' type='text' /><br />
  Subject: <input name='subject' type='text' /><br />
  Message:<br />
  <textarea name='message' rows='15' cols='40'>
  </textarea><br />
  <input type='submit' />
  </form>";
  }
?>

Can someone plase let me know where i am going wrong.

Thanx in advance.

Pedro